[RFC PATCH v2 4/4] rebase -i: allow --edit-todo with --exec

[Andrei Rybak <rybak.a.v@gmail.com>]

When using rebase, option --exec can be used, for example, to run tests
after every commit created by rebase.  When using interactive rebase, I
don't always know, if I would want to run something against each commit
before I start rebasing.  Sometimes, I realize this only after doing
some editing in the middle of the rebase.  To do that, I have to
manually edit the todo file.  Additing exec command by hand or
semi-automatically is cumbersome and error prone.  Especially if the
file is big or complex, e.g. when option --rebase-merges is used.

Allow using the --edit-todo action of git rebase with option --exec.
New test is based on test 'rebase --edit-todo can be used to modify
todo'.  Contents of todo file are checked using set_cat_todo_editor
similarly to what test 'respects rebase.abbreviateCommands with fixup,
squash and exec' does.

Remove unnecessary braces around call to usage_with_options, while we're
here.

TODO: Still need better validation of options. With current
      implementation, the following is not rejected:

	git rebase --edit-todo -x 'git show HEAD' --autostash

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
---
 Documentation/git-rebase.txt  |  3 ++-
 builtin/rebase.c              | 16 +++++++++++++---
 t/t3404-rebase-interactive.sh | 26 ++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 639a4179d1..b5db5e80d4 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -12,7 +12,8 @@ SYNOPSIS
 	[--onto <newbase> | --keep-base] [<upstream> [<branch>]]
 'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
 	--root [<branch>]
-'git rebase' (--continue | --skip | --abort | --quit | --edit-todo | --show-current-patch)
+'git rebase' (--continue | --skip | --abort | --quit |
+	--edit-todo [--exec<cmd>] | --show-current-patch)
 
 DESCRIPTION
 -----------
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 8a6ac7439b..4fd55cfbb4 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -33,7 +33,8 @@ static char const * const builtin_rebase_usage[] = {
 		"[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
 	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
 		"--root [<branch>]"),
-	N_("git rebase --continue | --abort | --skip | --edit-todo"),
+	N_("git rebase --continue | --abort | --skip | "
+		"--edit-todo [--exec <cmd>]"),
 	NULL
 };
 
@@ -409,6 +410,11 @@ static int run_rebase_interactive(struct rebase_options *opts,
 		break;
 	}
 	case ACTION_EDIT_TODO:
+		if (opts->cmd) {
+			ret = add_exec(opts->cmd);
+			if (ret)
+				break;
+		}
 		ret = edit_todo_file(flags);
 		break;
 	case ACTION_SHOW_CURRENT_PATCH: {
@@ -1565,15 +1571,19 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			     builtin_rebase_options,
 			     builtin_rebase_usage, 0);
 
-	if (action != ACTION_NONE && total_argc != 2) {
+	if (action != ACTION_NONE && action != ACTION_EDIT_TODO &&
+	    total_argc != 2)
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
-	}
 
 	if (argc > 2)
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
 
+	if (action == ACTION_EDIT_TODO && argc > 0)
+		usage_with_options(builtin_rebase_usage,
+				   builtin_rebase_options);
+
 	if (options.type == REBASE_PRESERVE_MERGES)
 		warning(_("git rebase --preserve-merges is deprecated. "
 			  "Use --rebase-merges instead."));
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index d2dfbe46b9..c3b640575d 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1082,6 +1082,32 @@ test_expect_success 'rebase --edit-todo can be used to modify todo' '
 	test L = $(git cat-file commit HEAD | sed -ne \$p)
 '
 
+test_expect_success 'rebase --edit-todo can be used with -x' '
+	test_when_finished "reset_rebase" &&
+	git reset --hard &&
+	git checkout no-conflict-branch^0 &&
+	cat >expected <<-EOF &&
+	pick $(git rev-list --abbrev-commit -1 HEAD^) L
+	exec git show HEAD
+	pick $(git rev-list --abbrev-commit -1 HEAD) M
+	exec git show HEAD
+	EOF
+	set_fake_editor &&
+	FAKE_LINES="1 edit 2 3 4" git rebase -i HEAD~4 &&
+	set_cat_todo_editor &&
+	test_must_fail git rebase --edit-todo -x "git show HEAD" >actual &&
+	test_cmp expected actual
+'
+
+test_expect_failure 'rebase --edit-todo -x does not allow other arguments' '
+	test_when_finished "reset_rebase" &&
+	git reset --hard &&
+	git checkout no-conflict-branch^0 &&
+	set_fake_editor &&
+	FAKE_LINES="1 edit 2 3 4" git rebase -i HEAD~4 &&
+	test_must_fail git rebase --edit-todo -x "git show HEAD" --autostash
+'
+
 test_expect_success 'rebase -i produces readable reflog' '
 	git reset --hard &&
 	git branch -f branch-reflog-test H &&
-- 
2.24.0.windows.2